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#include <linux/cpu.h>
#include <linux/dma-mapping.h>
#include <linux/gfp.h>
#include <linux/highmem.h>
#include <xen/features.h>
static DEFINE_PER_CPU(unsigned long, xen_mm32_scratch_virt);
static DEFINE_PER_CPU(pte_t *, xen_mm32_scratch_ptep);
static int alloc_xen_mm32_scratch_page(int cpu)
{
struct page *page;
unsigned long virt;
pmd_t *pmdp;
pte_t *ptep;
if (per_cpu(xen_mm32_scratch_ptep, cpu) != NULL)
return 0;
page = alloc_page(GFP_KERNEL);
if (page == NULL) {
pr_warn("Failed to allocate xen_mm32_scratch_page for cpu %d\n", cpu);
return -ENOMEM;
}
virt = (unsigned long)__va(page_to_phys(page));
pmdp = pmd_offset(pud_offset(pgd_offset_k(virt), virt), virt);
ptep = pte_offset_kernel(pmdp, virt);
per_cpu(xen_mm32_scratch_virt, cpu) = virt;
per_cpu(xen_mm32_scratch_ptep, cpu) = ptep;
return 0;
}
static int xen_mm32_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
int cpu = (long)hcpu;
switch (action) {
case CPU_UP_PREPARE:
if (alloc_xen_mm32_scratch_page(cpu))
return NOTIFY_BAD;
break;
default:
break;
}
return NOTIFY_OK;
}
static struct notifier_block xen_mm32_cpu_notifier = {
.notifier_call = xen_mm32_cpu_notify,
};
static void* xen_mm32_remap_page(dma_addr_t handle)
{
unsigned long virt = get_cpu_var(xen_mm32_scratch_virt);
pte_t *ptep = __get_cpu_var(xen_mm32_scratch_ptep);
*ptep = pfn_pte(handle >> PAGE_SHIFT, PAGE_KERNEL);
local_flush_tlb_kernel_page(virt);
return (void*)virt;
}
static void xen_mm32_unmap(void *vaddr)
{
put_cpu_var(xen_mm32_scratch_virt);
}
/* functions called by SWIOTLB */
static void dma_cache_maint(dma_addr_t handle, unsigned long offset,
size_t size, enum dma_data_direction dir,
void (*op)(const void *, size_t, int))
{
unsigned long pfn;
size_t left = size;
pfn = (handle >> PAGE_SHIFT) + offset / PAGE_SIZE;
offset %= PAGE_SIZE;
do {
size_t len = left;
void *vaddr;
if (!pfn_valid(pfn))
{
/* Cannot map the page, we don't know its physical address.
* Return and hope for the best */
if (!xen_feature(XENFEAT_grant_map_identity))
return;
vaddr = xen_mm32_remap_page(handle) + offset;
op(vaddr, len, dir);
xen_mm32_unmap(vaddr - offset);
} else {
struct page *page = pfn_to_page(pfn);
if (PageHighMem(page)) {
if (len + offset > PAGE_SIZE)
len = PAGE_SIZE - offset;
if (cache_is_vipt_nonaliasing()) {
vaddr = kmap_atomic(page);
op(vaddr + offset, len, dir);
kunmap_atomic(vaddr);
} else {
vaddr = kmap_high_get(page);
if (vaddr) {
op(vaddr + offset, len, dir);
kunmap_high(page);
}
}
} else {
vaddr = page_address(page) + offset;
op(vaddr, len, dir);
}
}
offset = 0;
pfn++;
left -= len;
} while (left);
}
static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle,
size_t size, enum dma_data_direction dir)
{
/* Cannot use __dma_page_dev_to_cpu because we don't have a
* struct page for handle */
if (dir != DMA_TO_DEVICE)
outer_inv_range(handle, handle + size);
dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, dmac_unmap_area);
}
static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle,
size_t size, enum dma_data_direction dir)
{
dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, dmac_map_area);
if (dir == DMA_FROM_DEVICE) {
outer_inv_range(handle, handle + size);
} else {
outer_clean_range(handle, handle + size);
}
}
void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
if (!__generic_dma_ops(hwdev)->unmap_page)
return;
if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
return;
__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
}
void xen_dma_sync_single_for_cpu(struct device *hwdev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
if (!__generic_dma_ops(hwdev)->sync_single_for_cpu)
return;
__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
}
void xen_dma_sync_single_for_device(struct device *hwdev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
if (!__generic_dma_ops(hwdev)->sync_single_for_device)
return;
__xen_dma_page_cpu_to_dev(hwdev, handle, size, dir);
}
int __init xen_mm32_init(void)
{
int cpu;
if (!xen_initial_domain())
return 0;
register_cpu_notifier(&xen_mm32_cpu_notifier);
get_online_cpus();
for_each_online_cpu(cpu) {
if (alloc_xen_mm32_scratch_page(cpu)) {
put_online_cpus();
unregister_cpu_notifier(&xen_mm32_cpu_notifier);
return -ENOMEM;
}
}
put_online_cpus();
return 0;
}
arch_initcall(xen_mm32_init);
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